MEXILETINE HYDROCHLORIDE (Mexiletine Hydrochloride)
What to know about MEXILETINE HYDROCHLORIDE — also sold as Mexiletine Hydrochloride: uses, side effects, interactions, and safety considerations for people taking it or caring for someone who is.
MEXILETINE HYDROCHLORIDE (brand names: Mexiletine Hydrochloride) is classified as Low risk (2 risk points) by AllMeds. It is a S4 medication under the TGA in Australia. FDA approved in the United States. Class IB antiarrhythmic with potential for CNS side effects including dizziness and tremor.
Key Takeaways
- TGA Schedule: S4 in Australia
- Risk level: Low (2 points)
Scheduling and Classification
| Jurisdiction | Classification | Status |
|---|---|---|
| Australia (TGA) | S4 | Not PBS listed |
| United States (FDA) | Rx only | FDA approved |
Risk Profile
Class IB antiarrhythmic with potential for CNS side effects including dizziness and tremor.
How MEXILETINE HYDROCHLORIDE is regulated
MEXILETINE HYDROCHLORIDE is overseen by medicines regulators in each country. The rules below explain how it's scheduled, what oversight applies, and what to discuss with your doctor or pharmacist before starting, changing, or stopping this medication.
Australia TGA / PBS / State Schemes
Classified as S4 under the Therapeutic Goods Administration (TGA).
WorkSafe Victoria Drugs of Dependence Guidelines require monitoring for all S8 opioids. WorkCover QLD Pain Intervention Guidelines recommend multimodal pain management with opioids as a last resort.
United Kingdom NICE / MHRA / FPM
NICE NG193 (Chronic Pain) recommends against initiating opioids for chronic primary pain. The Faculty of Pain Medicine (FPM) Opioids Aware resource recommends structured opioid prescribing with regular review, dose limits, and documented tapering plans.
For personal injury claims in the UK, opioid prescribing duration and dose should be reviewed against NICE and FPM guidelines. Costs may be recoverable as a disbursement in high-value PI claims.
United States FDA / CDC / State WC
FDA approved for use in the United States.
FDA Boxed Warning: BOXED WARNING WARNINGS Mortality In the National Heart, Lung and Blood Institute’s Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multicentered, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction more than six days but less than two years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups (3.0%). The average duration of treatment with encainide or flecainide in this study was ten months. The applicability of the CAST results to other populations (e.g., those without recent myocardial infarction) is uncertain. Considering the known proarrhythmic properties of mexiletine and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of mexiletine as well as other antiarrhythmic agents should be reserved for patients with life-threatening ventricular arrhythmia. Acute Liver Injury In postmarketing experience abnormal liver function tests have been reported, some in the first few weeks of therapy with mexiletine hydrochloride. Most of these have been observed in the setting of congestive heart failure or ischemia and their relationship to mexiletine hydrochloride has not been established.
The CDC Clinical Practice Guideline for Prescribing Opioids (2022) recommends non-opioid therapies as first-line treatment for pain. When opioids are prescribed, the lowest effective dose should be used for the shortest duration needed.
For workers compensation claims, many states require prior authorization for opioids beyond initial acute prescribing. State drug formularies (e.g. California MTUS, Texas, New York) may restrict or require step therapy before opioid approval.
New Zealand ACC / BPAC NZ / Medsafe
BPAC NZ recommends reassessing opioid therapy at regular intervals and limiting duration. The NZ Opioid Prescribing B-QuiCK Guide provides structured prescribing and tapering protocols.
ACC (Accident Compensation Corporation) covers treatment-related medications for accepted claims. Opioid prescribing beyond guidelines may require ACC clinical review and approval.
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Important: This page is general health information, not personal medical advice. If you have questions about your medication — including starting it, stopping it, changing the dose, or combining it with something else — speak with your doctor or pharmacist. For an emergency or suspected overdose, call your local emergency number or poison information service immediately. Information is drawn from regulator and clinical guideline sources (TGA, FDA, MHRA, NICE, PBS, CDC); see our methodology for details.